The invention relates to a portable apparatus and a method for detecting and reducing tension and stress in a human subject using bio feedback.
Stress is an everyday fact of life for millions of people. Stressful situations are often found in the workplace and at home. This stress can lead to long-term physical and psychological problems. Research has shown that stress can be reduced through the alteration of brain wave patterns that the brain uses in order to function. Stimuli, such as sound and light, can affect and actually alter the flow of these brain wave patterns.
Bio feedback systems are known in the art for use in detecting levels of stress in subjects and providing the appropriate stimuli to affect and alter the flow of brain wave patterns. Bio feedback systems monitor and process bioelectrical signals generated in specific topological regions of a human subject""s nervous system and produce a sensory stimulus when the system detects the presence or absence of certain characteristics in the signal. These characteristics may be correlated with a desired condition of the human subject""s nervous system. The sensory stimulus provided by the bio feedback system, typically an audio or visual stimulus, or a combination of the two, is fed back to the human subject who associates the presence of the stimulus with the goal of achieving the desired condition of the nervous system. By responding to the stimulus, the human subject can be trained to control the wave form patterns of the monitored bioelectrical signals and thereby control the nervous system. Such a bio feedback system is disclosed in U.S. Pat. No. 3,727,616 to Ross.
Because bio feedback devices operate on the basis of internal stimuli, that is stimuli produced in response to bioelectrical signals generated by the human subject, the success of the bio feedback device depends upon a human subject attempting to consciously control a state of stress. Many people cannot affect such control over their involuntary nervous systems. In addition, bio feedback systems are usually expensive, require complex equipment, and require an expert to operate.
Prior art devices have attempted to overcome these limitations by producing a state of mental harmonization or relaxation in a human subject without detecting the state of stress, that is, through the use of a program of external stimuli. However, such systems do not provide a stress detection system and, therefore, the stimuli cannot be tailored to a human subject""s changing state of stress and individual needs.
Tension and stress in human subjects may result in involuntary muscle movement. This muscle activity in the human body is initiated by electrical nerve impulses from the brain. These impulses may be measured at the surface of the skin as a voltage. The magnitude of the voltage signal is very small, on the order of micro volts. The magnitude of the electrical activity varies proportionately with the force of the muscle movement.
A small portable instrument is used to monitor residual muscle tension, as indicated by electrical activity from spurious motor neuron firings. The instrument is connected to one or more electrodes that receive electrical impulses created by activated nerves in the human subject""s muscle groups. A bio feedback signal is generated whenever tension exceeds a pre-set threshold and slows or stops as tension is reduced towards the threshold. This enables the user to learn how to voluntarily reduce excess muscle tension and lesson the harmful health effects caused by stress. The instrument is battery powered and is miniaturized to fit comfortably on a human subject, such as in a shirt pocket. Alternatively, the instrument may be attached to the clothing of the human subject by velcro or by a clip-on device, or may be attached to the body of the human subject using a band with a velcro fastener, for example.
In an embodiment, three electrodes are attached to the skin of the human subject, along a chosen muscle group. A sensitive instrument amplifier detects differential voltage, while rejecting common mode signals. The desired signals are isolated through a band pass filter, of approximately 100 Hz, for example. The signals are then amplified. Signals that exceed a set point are integrated and produce a feedback signal through a small speaker, at a rate proportional to the amount of muscle tension.
The electrodes may be attached to the human subject on a desired muscle group, such as the trapezius muscles (shoulder and back), for example.
The instrument is ideal for a person sitting at a desk, using a computer keyboard, or any other position or situation where a person has a tendency to build up tension and stress in the neck, shoulders and back muscles. Such stress, if not reduced, may cause disturbing irritability, headaches, shoulder pain, back pain, carpal tunnel syndrome, tingling and numbness in fingers, hands and arms, or any other pain associated with stress buildup.
The apparatus and method may be used by the human subject to learn when tension and stress will occur. By repeatedly using the apparatus, the human subject will learn what activities or conditions are likely to cause high levels of tension and stress. The human subject can then modify or avoid the activities or conditions so as to prevent the buildup of harmful stress.